Factory firmware for the M5Stack Unit CardKB2 (SKU: U215), built with ESP-IDF. It provides matrix keyboard scanning, RGB status LED, and key output over I2C / UART / ESP-NOW / BLE HID—including manufacturing / QA hooks such as I2C-triggered production-test mode.
| Mode | Description |
|---|---|
| I2C (default) | I2C slave reports characters / key data to the host. |
| UART | Custom frames with key index and press / release over UART. |
| ESP-NOW | Broadcasts key frames (similar framing to UART). |
| BLE HID | Bluetooth HID keyboard, including arrow keys via Fn combos. |
Hold Fn + Sym, then press 1 / 2 / 3 / 4 on the top number row to select I2C / UART / ESP-NOW / BLE HID respectively.
Note: Fn + 1 alone (top-left number key) sends ESC in most modes; it does not switch modes.
- idf version: ESP-IDF v6.1-dev-dirty
cd src
idf.py set-target esp32c61
idf.py build
idf.py -p <PORT> flash monitorAfter building, generate a single flash image from the bootloader, partition table, and app binaries:
esptool --chip esp32c61 merge-bin \
-o UnitCardKB2-ESP32C61-Factory-V2_0x00.bin \
--flash-mode dio \
--flash-freq 80m \
--flash-size 2MB \
0x0 build/bootloader/bootloader.bin \
0x8000 build/partition_table/partition-table.bin \
0x10000 build/main.binFlash the merged binary:
esptool --chip esp32c61 -p /dev/ttyACM0 -b 1500000 write-flash 0x0 UnitCardKB2-ESP32C61-Factory-V2_0x00.binThis project is licensed under the MIT License—see LICENSE.